Abstract

Aim/Background

Most of patients with lung adenocarcinoma harboring activating mutations in epidermal growth factor receptor (EGFR M+) are treated with cytotoxic chemotherapy after the failure of EGFR-TKIs. It still remains unclear whether the efficacy of chemotherapy for patients with EGFR M+ is equivalent to that for the patients with EGFR wild type (WT).

Methods

We retrospectively analyzed outcome of the EGFR M+ patients who received platinum-doublet chemotherapy following the failure of TKI-treatment between May 2007 and February 2015, in the National Cancer Center Hospital. Patient characteristics, efficacy of chemotherapy and survival were compared with those of EGFR WT patients who received first-line platinum-doublet treatment.

Patient characteristics

EGFR M+ group
n = 75 (%)

EGFR WT group
n = 96 (%)

Age

Median (range)

63 (26-81)

65 (27-76)

Sex

Male

33 (44)

70 (73)

Female

42 (56)

26 (27)

Stage

III B

0

7 (7)

IV

57 (76)

71 (74)

Rec

18 (24)

18 (19)

ECOG PS

0

21 (28)

46 (48)

1

47 (63)

49 (51)

2

4 (5)

1 (1)

unknown

3 (4)

0

Type of EGFR mutation

Exon 19

45 (60)

0

Exon 21

30 (40)

0

Platinum-doublet regimen

CDDP + PEM

58 (77)

53 (55)

CBDCA + PTX + Bev

8 (11)

21 (22)

Others

9 (12)

22 (23)

Response to chemotherapy

PR

15 (20)

38 (40)

SD

41 (55)

42 (44)

PD

16 (21)

12 (12)

NE

3 (4)

4 (4)

Results

A total of 338 patients were diagnosed as EGFR-M+ lung cancer and 246 patients received EGFR-TKIs as the first-line chemotherapy. Failure of EGFR-TKIs was confirmed in 183 patients, and treatment with second-line platinum-doublet chemotherapy was given in 75 patients. Ninety-six consecutive cases who were diagnosed as EGFR WT lung adenocarcinoma and received first-line platinum-doublet were collected. Response rate of platinum-doublet chemotherapy in EGFR M+ and EGFR WT group was 20 % and 40 % (p = 0.04). Progression-free survival (PFS) of the platinum-doublet chemotherapy did not differ significantly between the EGFR M+ group and EGFR WT group (median, 175 vs 161 days, p = 0.86). Overall survival time since the start of platinum-doublet chemotherapy tended to be longer in the EGFR M+ group than in the EGFR WT group (median, 631 vs 450 days, p = 0.18).

Conclusions

When survival time since the start of platinum-doublet chemotherapy was compared between the patients with EGFR M+ previously treated with EGFR-TKIs and with EGFR WT, PFS did not differ in groups, but OS tended to be longer in the EGFR M+ group.